Conditioner and conditioning methods for smooth pads

ABSTRACT

Pad conditioners and methods of conditioning pads for applications such as polishing substrates and chemical mechanical planarization of substrates are provided.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. patent application Ser.No. 60/368,048 filed Mar. 25, 2002 and U.S. patent application Ser. No.60/368,049 filed Mar. 25, 2002. This application is related to U.S.patent application Ser. No. 10/020,081, filed Dec. 11, 2001, and U.S.patent application Ser. No. 10/020,082, filed Dec. 11, 2001. Thecontents of all of these applications are incorporated herein by thisreference in their entirety.

TECHNICAL FIELD

[0002] This invention relates to conditioners and methods forconditioning pads for applications such as chemical mechanicalplanarization (CMP) and polishing of substrates such as semiconductorsubstrates, wafers, metallurgical samples, memory disk surfaces, opticalcomponents, lenses, and wafer masks. More particularly, the presentinvention relates to conditioners for CMP pads and pads for polishingand methods of maintaining pads during CMP and polishing processes forfabrication of electronic devices.

BACKGROUND

[0003] Processes employing CMP or polishing techniques have been widelyused to planarize the surface of wafers during the various stages ofdevice fabrication in order to improve yield, performance, andreliability of the fabrication process. In fact, CMP has becomeessentially indispensable on behalf of the fabrication of advancedintegrated circuits.

[0004] Integrated circuits are chemically and physically integrated intoa substrate by patterning regions in the substrate and layers on thesubstrate. To achieve high yields, it is usually necessary to recreate asubstantially flat substrate after processing steps that leavetopographic features on the surface of the wafer, features such assurface irregularities, bumps, troughs, and trenches.

[0005] One type of commonly used pad for applications such as polishingand CMP of substrates is a fiber pad such as a felt pad. The felt pad isa composite of fibers impregnated with a resin. Felt pads offer manyunique advantages compared to non-fiber pads like pure polyurethanepads. Some examples of the advantages are low cost of ownership and goodnon-uniformity for the CMP process. However, the standard methods of padconditioning and the standard materials for pad conditioning may beunsuitable for use with fiber CMP pads such as felt pads. Particularly,the standard conditioning methods and materials are not easily adoptedfor use with fiber based pads because the combination does not allow forgood planarization efficiency.

[0006] There is a need for improved pad conditioners and improvedmethods for conditioning pads such as fiber pads like resin impregnatedfelt pads. More particularly, there is a need for improved padconditioners and methods of pad conditioning for resin impregnated feltpads so that the pads can perform with higher planarizationefficiencies. In addition, there is a need for new pad conditioners andconditioning methods that allow the pad to be used for longer periods oftime before the pad must be replaced.

SUMMARY

[0007] This invention pertains to improve pad conditioners and methodsof conditioning pads for applications such as polishing substrates andCMP of substrates and related methods. The present invention seeks toovercome one or more of the deficiencies of the standard technologiesfor polishing and/or planarizing substrates.

[0008] One aspect of the present invention includes a pad conditionerfor applications such as polishing substrates and CMP of substrates. Anembodiment of the present invention is a pad conditioner for CMP ofsubstrates for electronic device fabrication. Another aspect of thepresent invention is a method for conditioning pads for applicationssuch as polishing substrates and CMP of substrates.

[0009] Still another aspect of the present invention includes anapparatus for applications such as polishing substrates and CMP ofsubstrates. In one embodiment, the apparatus includes a support forholding a pad for polishing substrates and/or CMP of substrates. Theapparatus further includes a pad conditioner according to the teachingsof the present disclosure.

[0010] It is to be understood that the invention is not limited in itsapplication to the details of construction and to the arrangements ofthe components set forth in the following description or illustrated inthe figures. The invention is capable of other embodiments and of beingpracticed and carried out in various ways. In addition, it is to beunderstood that the phraseology and terminology employed herein are forthe purpose of description and should not be regarded as limiting.

[0011] As such, those skilled in the art will appreciate that theconception, upon which this disclosure is based, may readily be utilizedas a basis for the designing of other structures, methods and systemsfor carrying out aspects of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

[0012] Further, the purpose of the foregoing abstract is to enable thePatent Office and the public generally, and especially the scientists,engineers and practitioners in the art who are not familiar with patentor legal terms or phraseology, to determine quickly from a cursoryinspection the nature and essence of the technical disclosure of theapplication. The abstract is not intended to define the invention of theapplication, which is measured by the claims, nor is the abstractintended to be limiting as to the scope of the invention in any way.

[0013] The above and still further features and advantages of thepresent invention will become apparent upon consideration of thefollowing detailed descriptions of specific embodiments thereof,especially when taken in conjunction with the accompanying figures.

DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a diagram of an embodiment of the present invention.

[0015]FIG. 2 is a diagram of an embodiment of the present invention.

[0016]FIG. 3 is a diagram of an embodiment of the present invention.

[0017]FIG. 4 is a diagram of an embodiment of the present invention.

[0018] Skilled artisans appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

DESCRIPTION

[0019] The operation of embodiments of the present invention will bediscussed below, primarily, in the context of chemical mechanicalplanarization of substrates for electronic devices. However, it is to beunderstood that embodiments in accordance with the present invention maybe used for general applications such as CMP and substrate polishingsuch as grinding, lapping, shaping and polishing of semiconductorsubstrates, wafers, metallurgical samples, memory disk surfaces, opticalcomponents, lenses, and wafer masks.

[0020] An embodiment of the present invention is an improved polishingpad conditioner for substantially maintaining polishing pad performance.More particularly, one embodiment of the present invention is apolishing pad conditioner for applications such as chemical mechanicalplanarization such as that used as part of integrated circuitmanufacturing processes. Another embodiment of the present inventionincludes methods for performing chemical mechanical planarization.

[0021] Embodiments of the present invention are particularly suitablefor use with an improved polishing pad for applications such as chemicalmechanical planarization. One embodiment of the present invention is apad conditioner for chemical mechanical planarization of substrates forelectronic device fabrication; the pad conditioner maintains thepolishing surface of a fiber pad sufficiently smooth so that the pad iscapable of providing effective planarization. In other words, padconditioners according to embodiments the present invention are capableof conditioning pads that are capable of providing planarizationefficiencies that are suitable for industrial processes such as chemicalmechanical planarization. Preferably, the planarization efficiencies arehigh enough to meet the specifications for processing the work pieces.

[0022] Reference is now made to FIG. 1 where there is shown a side viewof an embodiment of a pad conditioner 15 according to the presentinvention. Pad conditioner 15 includes a conditioner body 20 having aconditioning surface 25. Conditioning surface 25 includes an abrasivesurface for abrading the polishing surface of a pad for applicationssuch as chemical mechanical planarization and polishing substrates.

[0023] Pad conditioners according to embodiments of the presentinvention have physical features different from those of standardconditioners. Conditioning surface 25 comprises abrasive particles.Optionally, conditioner body 20 may include a metal disk where one sideof the disk comprises conditioning surface 25 (see FIG. 2). Theparticles may be directly bonded to conditioning surface 25 ofconditioner body 20. For embodiments of the present invention, theparticles have a grit greater than about 200. More preferably, theparticle grit is greater than about 300 and for some applicationsgreater than 400.

[0024] In some embodiments of the present invention, the particles havesizes in the range of the about 1 micrometer to about 50 micrometers andall ranges subsumed therein. One embodiment of the present inventionincludes a pad conditioner that comprises abrasive particles bonded to acarrier and the particles are less than about 30 micrometers in size.For some applications, a more preferred embodiment of the conditionercomprises abrasive particles bonded to a carrier and the particles areless than are about 15 micrometers in size.

[0025] For some embodiments of the present invention, the spacingbetween the particles is also important. For some embodiments of thepresent invention, the particles have nearest neighbors spacings lessthan about 4 times the size of the particles. Preferably, the averagenearest neighbor spacing between the particles is in the range of about4 times the size of the particles to about 0 and all subranges subsumedtherein. In one embodiment, the particles have an average nearestneighbor spacing less than about 3 times the size of the particles. Inyet another embodiment, the particles have an average nearest neighborspacing less than about 2 times the size of the particles.

[0026] Another embodiment of the present invention includes a padconditioner for conditioning resin impregnated fiber pads in which thedistance that the abrasive particles protrude from the surface ispreferably less than or about equal to the average diameter of thefibers in a resin impregnated fiber pad for which the conditioner willbe used. In yet another embodiment, the average nearest neighbordistance between the abrasive particles is less than or equal to theaverage diameter of the fibers in a resin impregnated fiber pad forwhich the conditioner will be used.

[0027] In contrast to pad conditioners according to embodiments of thepresent invention, the standard technology conditioners use largerabrasive particles such as particles having grit less than about 200. Incontrast to preferred embodiments of the present invention, the standardtechnology pad conditioners typically have the particles more widelydispersed, i.e., larger nearest neighbor distances, than for preferredembodiments of the present invention.

[0028] Clearly, the differences in the physical properties between padconditioners according to embodiments of the present invention and padconditioners according to the standard technology will result indifferent conditioning characteristics. The apparatus and methodology ofthe standard technology for pad conditioning are directed toward makingthe surface of the pad rougher. Making the pad surface rougher is easilyaccomplished with the physical properties of the standard technology padconditioners.

[0029] However, for embodiments of the present invention, it ispreferred that the conditioning process and conditioning equipment areused to make the surface of the pad smoother. In other words, one of thefunctions of pad conditioners and methods of conditioning according toembodiments of the present invention is to substantially maintain asmooth surface for the pad. As a result of maintaining the smoothsurface finish, the pad is capable of providing effective planarizationefficiency or further improved planarization efficiency.

[0030] The capabilities of embodiments of the present invention arehighly advantageous for CMP processes using resin impregnated fiberpads. Preferably, fiber pads capable of providing effectiveplanarization efficiency have a substantially smooth planarizingsurface. However, the planarizing process causes the surface of fiberpads to become rougher which reduces the planarization efficiency. Thesmoothing capabilities of embodiments of the present invention returnthe planarizing surface of the pad to a substantially smooth surfacefinish capable of providing effective planarization.

[0031] With this new type of conditioning device and conditioningmethods according to embodiments of the present invention, resinimpregnated fiber pads such as felt pads can be used for applicationsthat require good planarization or effective planarization, such asdielectric planarization and copper CMP. In other words, someembodiments of the present invention can increase the performance ofpads such as fiber pads for applications like CMP and polishingsubstrates. In some instances, embodiments of the present invention canincrease the number of applications for which resin impregnated fiberpads can be used.

[0032] Reference is now made to FIG. 3 where there is shown a side viewof another embodiment of a pad conditioner 30 according to the presentinvention. Pad conditioner 30 includes a conditioner body 35 and acarrier 40 attached to conditioner body 35. Carrier 40 has aconditioning surface 45. Conditioning surface 45 includes an abrasivesurface for abrading the polishing surface of a pad for applicationssuch as chemical mechanical planarization and polishing substrates.

[0033] In a preferred embodiment, carrier 40 serves as a support uponwhich abrasive particles such as diamond particles are bonded so as toform conditioning surface 45. Carrier 40 may be a flexible material thatis attachable to conditioner body 35; conditioner body 35 may serve as arigid holder. Optionally, conditioner body 35 may include a metal diskand carrier 40 is attached to the surface of the disk. Variousattachment methods may be used for attaching carrier 40 to conditionerbody 35. Examples of attachment methods are mechanical attachmentmethods and adhesive attachment methods. Preferred attachment methodsare those that allow carrier 40 to be removed and replaced substantiallywithout damaging conditioner body 35.

[0034] For the embodiments of the present invention, the particles havea grit greater than about 200. More preferably, the particle grit isgreater than about 300 and for some applications greater than 400. Stillmore preferably, the particles have sizes in the range of the about 1micrometer to about 50 micrometers. One embodiment uses particles lessthan about 30 micrometers in size; another embodiment uses particlesless than about 15 micrometers in size. Conditioning surface 45 may haveessentially the same abrasive properties as described for conditioningsurface 25 for the embodiment described in FIG. 1.

[0035] Reference is now made to FIG. 4 where there is shown a side viewof elements of an apparatus 50 for conditioning a pad for applicationslike chemical mechanical planarization of substrates and polishingsubstrates. Apparatus 50 is similar to standard apparatus commonly usedfor applications like chemical mechanical planarization of substratesand polishing substrates with the exception of having a pad conditioner15 where pad conditioner 15 is essentially the same as that describedfor FIG. 1. Apparatus 50 also includes a pad support 55. Support 55 iscapable supporting a pad during pad conditioning. FIG. 4 shows a pad 60in order to illustrate the operation of support 55 and conditioner body20. During conditioning, apparatus 50 causes pad conditioner 15 tocontact pad 60 held on support 55. Optionally, support 55 may comprise aturntable for rotating pad 60 during conditioning. It is to beunderstood that other types of pad support may be used for embodimentsof the present invention. Optionally, apparatus 50 may include a padconditioner like pad conditioner 30 described for the embodiment shownin FIG. 3 instead of pad conditioner 15.

[0036] Pad conditioners according to embodiments of the presentinvention may use abrasive particles typically use for pad conditioningor other abrasive applications. Examples of suitable abrasive particlesare diamond particles, aluminum oxide particles, silicon carbideparticles, zirconia particles, and boron nitride particles. Optionally,the particles may be anchored with a metal such as nickel. A preferredembodiment of the present invention includes particles of diamondanchored in electroplated nickel pellets. The nickel is bonded to acarrier.

[0037] Another embodiment of the present invention includes an apparatusfor conditioning a pad for at least one of chemical mechanicalplanarization and polishing a substrate. The apparatus comprises a padconditioner having an abrasive surface. Preferably, the abrasive surfaceis capable of producing the minimum surface roughness for the padsurface for a size of abrasive particles. Preferably, the abrasiveparticles are less than 50 micrometers in size. The apparatus alsoincludes a pad support for supporting the pad. The pad conditioner andpad support are coupled so as to allow the pad conditioner to conditionthe pad. In other words, the apparatus is capable of allowing the padconditioner to contact the pad to allow conditioning the pad. The padsupport of the apparatus may comprise a turntable. Optionally, the padsupport may include one or more rollers for a belt pad.

[0038] Descriptions of pad conditioning methods according to embodimentsof the present invention will now be presented. One embodiment of thepresent invention includes a method of conditioning a resin impregnatedfiber pad. The method includes the step of abrading the surface of thepad with particles having an average size less than 2 times the averagediameter of the fibers. In another embodiment of the present invention,the method includes the step of abrading the surface of the pad withparticles having an average size less than 1 times the average diameterof the fibers.

[0039] Some embodiments of the present invention may also includeconditioning a resin impregnated fiber pad wherein the step of smoothingthe surface of the pad is performed so that the surface finish of thepad after conditioning is smoother than that of the pad beforeconditioning. In other words, the method involves using the polishingsurface of the pad for a process such as CMP and polishing a substrateand having the average roughness of the polishing surface of the padprior to conditioning higher than the average roughness of the polishingsurface of the pad after conditioning. In another embodiment of thepresent invention, the method of conditioning a resin impregnated fiberpad includes the step of smoothing the surface of the pad with anabrasive comprising abrasive particles supported on a substantiallysolid surface. For this embodiment, the particles have an averagenearest neighbor spacing less than about 4 times the average size of theparticles. In addition, the particles have an average size in the rangeof about 1 micrometer to about 50 micrometers and all ranges subsumedtherein. In another embodiment, the particles have an average nearestneighbor spacing less than about 2 times the average size of theparticles. In yet another embodiment, the particles have an averagenearest neighbor spacing less than about 1 times the size of theparticles.

[0040] For some embodiments of the present invention, the step ofsmoothing the surface comprises abrading the surface with abrasiveparticles. The particles are bonded to a carrier and the particles areless than 50 micrometers in size. The step of smoothing continues untilthe surface attains the minimum surface roughness for the particle size.

[0041] The next four examples provide descriptions of examples of thetypes of pads for which embodiments of the present invention may beused. It is to be understood that the examples given in the presentapplication are merely exemplary of the types of pad for whichembodiments of the present invention are applicable. These examples arenot intended as limitations of the present invention. In other words,the conditioners and methods of conditioning according to embodiments ofthe present invention can be used with but are not limited to padsdescribed in the following three examples.

EXAMPLE 1

[0042] Various manufacturing techniques can be used to produce polishingpads for use with embodiments of the present invention. In oneembodiment, the polishing pad includes non-woven fibers comprisingpolyester and a polymer resin comprising polyurethane. Desirableproperties for polishing pads according to embodiments of the presentinvention can be produced using polyester fibers having a denier ofabout 2. Those skilled in the art know that polishing pads can also bemade using other deniers, such as for example, deniers in the range ofabout 1.5 to about 3.0.

[0043] Desirable properties for the polishing pads can be incorporatedinto the polishing pads by increasing the ratio of fiber to polymerresin in the polishing pad. For some embodiments, the ratio of polyesterfiber to polyurethane resin is in the range of from about 50:50 to about65:35, and all ratios and ratio ranges subsumed therein. In other words,the polyester makes up from about 50% to about 65% and subrangessubsumed therein. The polyurethane resin makes up from about 50% toabout 35% and subranges subsumed therein. Preferred embodiments of thepads have ratios of polyester to polyurethane of about 55:45.

[0044] Some starting materials for the pads have a Shore D hardness fromabout 45 to about 65 and all subranges subsumed therein. A preferred padhas a Shore D hardness from about 47 to about 57 and all subrangessubsumed therein. A more preferred pad has a Shore D hardness from about51 to about 54.

[0045] Table 1 summarizes several physical properties of an example ofstarting materials for fabricating pads that may be used withembodiments of the present invention. The pads, according to someembodiments, will also have properties like those listed in Table 1 inaddition to having a substantially smooth surface for CMP. TABLE 1Property Typical Preferred Pad Density gm/cc 0.5-0.7 0.58 +/− 0.04 Fiberto Polymer Resin Ratio 50:50-65:35 55:45 Hardness, Shore D >47 51-54Hardness, Shore A 89-98 Felt Density gm/cc 0.32 Pore Size Range um 5-150Compressibility % 1.8 Resiliency % 70-100 >80

[0046] Pads for some embodiments of the present invention were producedby using starting material having properties substantially the same asthose described in Table 1. A surface of the starting material was givena surface finish sufficiently smooth to allow effective planarizationefficiency. For this particular example, the surface finish was producedby buffing the surface of the starting material with a 30 micrometergrit abrasive belt to remove an amount of material from the surface ofthe starting material. In this example about 50 micrometers of materialwas removed from the surface. The surface was also buffed with a 15micrometer grit abrasive belt to remove an amount of material from thesurface of the starting material. In this example, about 50 micrometersof material were removed from the surface. The buffed surface had asmooth surface finish suitable for use for planarizing work pieces.Example applications that the pad was suitable for use in include oxideand shallow trench isolation CMP and for copper metallization CMP.

[0047] The planarization capabilities of pads according to the inventionpresented in this example have been measured. In addition, similarmeasurements have been performed for pads having similar properties butwithout the smooth polishing surface. The experimental results, ingeneral, show that pads according to this example have superiorplanarization capability over that of the pads without the smoothpolishing surface. Specifically, embodiments of the present inventionhave increased planarization efficiency, decreased erosion, anddecreased dishing for CMP processes. One of the pads according to anembodiment of the present invention included a polyester feltimpregnated with a polyurethane resin; the pad had a density of about0.59 grams per cubic centimeter, a compressibility of about 1.8 percent,and a rebound of about 85 percent. The polishing surface of the pad hada surface finish produced by buffing the polishing surface of the pad sothat the pad had a sufficient surface finish capable of providingeffective planarization efficiency.

EXAMPLE 2

[0048] A method of fabricating a starting material for embodiments ofthe present invention includes providing a polymer sheet that has anon-woven felt impregnated with a thermoplastic polymer. The sheet has adensity less than about 0.7 grams per cubic centimeter, and the sheethas a substrate contacting area. The method further includes the stepsof heating the area a sufficient amount and contemporaneously applying asufficient amount of mechanical pressure so that the density of thesheet increases to greater than about 0.7 grams per cubic centimeter.Polishing pads according to some embodiments of the present inventionhave densities in the range of from about 0.5 grams per cubic centimeterto about 1.2 grams per cubic centimeter.

[0049] Embodiments of the present invention have been used to produce apad having a density of about 1.03 grams per cubic centimeter. The padwas made from a starting polymer sheet comprising a non-woventhermoplastic resin impregnated felt having a density of about 0.59grams per cubic centimeter. During the process, the thickness of thesheet was decreased from an initial thickness of about 0.049 inches(1.24 mm) to a post-process thickness of about 0.027-0.028 inches(0.68-0.71 mm). The thickness decrease produced a substantiallycorresponding increase in the density of the polymer sheet. The hardnessof the polymer sheet also increased. The pad fabricated from the sheet,after the heat and pressure processing, was more dense and harder thanthe starting polymer sheet.

[0050] In one configuration, a polymer sheet having a nonwoven felt,such as a polyester, impregnated with a thermoplastic resin, such as apolyurethane, was used as a starting polymer sheet. The starting polymersheet had a Shore D hardness of about 50. The application of sufficientheat and pressure to the starting polymer sheet produced an increase inthe hardness of the sheet to a Shore D hardness of about 60-62.

[0051] Some embodiments of the present invention have a Shore D hardnessfrom about 50 to about 65 and all subranges subsumed therein. Preferablyfor some applications, pads made for embodiments of the presentinvention have a Shore D hardness of at least about 60. Preferredembodiments have a Shore D hardness from about 60 to about 62 and allsubranges subsumed therein.

[0052] For some applications, a preferred starting material is a pad forCMP that includes a polymer composite having a non-woven felt of polymerfibers impregnated with a resin. To produce the pad, the polymercomposite is subjected to heat and pressure so that the composite has adensity greater than about 0.70 grams per cubic centimeter. In addition,the composite has a Shore D hardness of at least 60.

[0053] As indicated earlier, the process conditions for embodiments ofthe present invention will be determined in part by properties of thestarting polymer sheet. The following example provides processconditions that have been used for fabricating starting materials forembodiments of the present invention. In this example, the polymer sheetincludes a nonwoven felt of polymer fibers such as, for example,polyester fibers or nylon fibers. The felt is impregnated with a resinsuch as, for example, a thermoplastic polyurethane. The polymer sheethas dimensions of about 10.5 inches×10.5 inches and a thickness of about0.05 inches. The polymer sheet is placed between two substantiallysmooth steel surfaces. The steel surfaces are heated to about theselected processing temperature. Suitable processing temperatures forthis example are in the range of from about 300 degrees F. (149 degreeC.) to about 450 degrees F. (232 degree C.), including all temperaturesand ranges of temperatures subsumed therein. Preferred temperatures arein the range of about 375 degrees F. (191 degree C.) to about 400degrees F. (204 degrees C.), including all temperatures and ranges oftemperatures subsumed therein.

[0054] Preferably, though it may not be required, the polymer sheet isallowed to contact the heated surfaces for a period of time so that thetemperature of the polymer sheet increases to about the temperature forprocessing. In other words, the sheet may be preheated beforeapplication of the high pressure. In this example, the polymer sheet wasallowed to heat for about 20 seconds. After heating, pressure wasapplied to the polymer sheet via the steel surfaces. Suitable pressuresfor embodiments of the present invention are pressures greater thanabout 1500 psi (10.3 megapascals). Preferably, the pressures are greaterthan about 2500 psi (17.2 megapascals). Some particularly good resultswere obtained using a processing pressure of about 2900 psi (20megapascals).

[0055] For some of the experiments, a pressure of about 2900 psi (20megapascals) was applied for a period of about 10 seconds. For otherexperiments using a pressure of about 2900 psi (20 megapascals), thepressure was applied for a period of about 10 seconds followed by a180-degree rotation within the plane of the sheet and then followed byanother application of pressure at 2900 psi (20 megapascals) for aperiod of about 10 seconds. The two-step pressure application resultedin greater uniformity of properties of the polymer sheet. It is to beunderstood that the equipment used for this experiment may not have beenoptimized for process uniformity and, therefore, should not beconsidered as a limitation for practicing the present invention.

[0056] Following the application of heat and pressure, the sheet wasallowed to cool while sandwiched between two substantially flat platesof aluminum. The plates of aluminum were arranged to provide sufficientpressure to keep the polymer sheet substantially flat during at leastpart of the cooling step so as to prevent the formation of wrinkles orwaves in the surface of the polymer sheet.

[0057] A polymer sheet having a thickness of about 0.050 inches (1.3 mm)was heated to a temperature in the range of about 375 degrees F. (191degrees C.) to about 400 degrees F. (204 degrees C.). Pressure wasapplied to the heated polymer sheet until the polymer sheet wascompressed to a predetermined thickness fixed by a physical stop havinga thickness of about 0.020 inches (0.51 mm). After removal of thepressure and the heat, the polymer sheet had a thickness of about 0.030inches (0.76 mm). It is to be stood that the starting thickness of thepolymer sheet for this example is for purposes of illustration. Otherthicknesses can be used for the starting material thickness.

[0058] For the previous example, heated plates were used for carryingout the processing steps. As known by those skilled in the art, analternative would be to use heated rollers for applying the heat andpressure. In addition, other known techniques for heating and applyingpressure can be used in embodiments of the present invention.

[0059] Embodiments of the present invention can be used to produce padshaving substantially selectable porosity and density profiles throughthe thickness of the pad. In other words, by selecting the processingconditions of temperature, pressure, and time duration of theirapplication, the porosity profile near the surface of the pad may differfrom that of the profile away from the surface at locations near themiddle of the thickness of the pad, i.e., the midpoint of the padthickness. Optionally, heat may be applied to both sides of the startingpolymer sheet or heat may be applied to only one side of the polymersheet so as to achieve selectable density profiles through the thicknessof the pad.

[0060] Table 2 summarizes several physical properties of startingmaterials for some embodiments of polishing pads according to thepresent invention. Exemplary pads for use with embodiments of thepresent invention will also have properties like those listed in TABLE 2in addition to having a substantially smooth surface for CMP. TABLE 2Property Suitable Preferred Pad Density gm/cc 0.5-1.2 about 1 Fiber toPolymer Resin Ratio 55:45 Hardness, Shore D >about 50 60-62 Felt Densitygm/cc 0.32

[0061] Pads for use with embodiments of the present invention can beproduced by using starting material having properties substantially thesame as those described in Table 2. A surface of the starting materialcan be given a surface finish sufficiently smooth to allow effectiveplanarization or effective planarization efficiency. For this particularexample, the surface finish can be produced by buffing the surface ofthe starting material with a 30 micrometer grit abrasive belt to removeand amount of material from the surface of the starting material. Inthis example, about 50 micrometers of material may be removed from thesurface. The surface can be buffed with a 15 micrometer grit abrasivebelt to remove an amount of material from the surface of the startingmaterial. In this example, about 50 micrometers of material may beremoved from the surface. The buffed surface is expected to have asmooth surface finish suitable for use for planarizing work pieces andhave a higher planarization efficiency than may be possible without thesmooth surface according to the present invention.

[0062] Specifically, one embodiment of the present invention is a padconditioner for pads prepared according to the present disclosure forCMP of a substrate for the purpose of forming at least one of: shallowtrench isolation structures, interlayer dielectric structures,intermetal dielectric structures, and copper metallization structures.

EXAMPLE 3

[0063] Various types of pads have been developed in efforts to meet theneeds of CMP processes and polishing processes. For a more detaileddiscussion of representative types of pads see PCT application W096/15887, the specification of which is incorporated herein byreference. Other representative examples of pads and methods of theirfabrication are described in U.S. patents U.S. Pat. No. 4,511,605, U.S.Pat. No. 4,708,891, U.S. Pat. No. 4,728,552, U.S. Pat. No. 4,841,680,U.S. Pat. No. 4,927,432, U.S. Pat. No. 5,533,923, U.S. Pat. No.6,126,532, U.S. Pat. No. 6,231,434, and U.S. Pat. No. 6,287,185, thespecifications of which are also each incorporated herein in theirentirety by this reference. Pads according to the present invention canbe fabricated using the methods and starting materials described in thepreviously listed patents and patent applications. The polishingsurfaces of those pads can be given a surface finish that can besubstantially maintained using the methods disclosed in the presentinvention so as to produce pads having a higher planarization efficiencythan is obtainable without the smooth polishing surface, as described inthe present disclosure.

EXAMPLE 4

[0064] Surface Roughness parameters where measured for an example padsuitable for use with an embodiment of the present invention. In otherwords, the measurements were made for a pad that may be used accordingto one of the method embodiments of the present invention and with oneof the apparatus embodiments of the present invention. The measurementswere made according to the DIN 4776 Standard (German Institute forStandardization).

[0065] The following are definitions of measurement parameter notations:

[0066] Rk—Core Roughness Depth—Depth of the roughness core profile.

[0067] Rpk—Reduced peak height—Average height of protruding peaks abovethe core profile.

[0068] Rvk—Reduced valley depth—Average depth of the profile valleysprojecting thorough the roughness core profile.

[0069] Mr1—Material Portion Mr1.

[0070] Mr2—Material Portion Mr2.

[0071] Surface roughness parameters were measured for a pad fabricatedaccording to the method of Example 1, supra. The measurement values forthis embodiment of the present invention were Rk from about 2 to about15, Rpk from about 0.5 to about 5, Rvk from about 8 to about 20, Mr1from about 1 to about 8, and Mr2 from about 68 to about 78. It is to beunderstood that the measured parameters are provided merely as anillustration of one example of a pad suitable for use with an embodimentof the present invention.

[0072] While there have been described and illustrated specificembodiments of the invention, it will be clear that variations in thedetails of the embodiments specifically illustrated and described may bemade without departing from the true spirit and scope of the inventionas defined in the appended embodiments and their legal equivalents.

[0073] In the foregoing specification, the invention has been describedwith reference to specific embodiments. However, one of ordinary skillin the art appreciates that various modifications and changes can bemade without departing from the scope of the present invention as setforth in the claims below. Accordingly, the specification and figuresare to be regarded in an illustrative rather than a restrictive sense,and all such modifications are intended to be included within the scopeof present invention.

[0074] Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or element of any or all the claims.

[0075] As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having,” “at least one of,” or any other variationthereof, are intended to cover a non-exclusive inclusion. For example, aprocess, method, article, or apparatus that comprises a list of elementsis not necessarily limited only to those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

What is claimed is:
 1. A method of conditioning a pad for at least oneof chemical mechanical planarization and polishing a substrate, themethod comprising the step of smoothing the surface of the pad so thatthe surface finish of the pad after conditioning is smoother than thatof the pad before conditioning.
 2. The method of claim 1 wherein theaverage roughness of the polishing surface of the pad prior toconditioning is higher than the average roughness of the polishingsurface of the pad after conditioning.
 3. The method of claim 1 whereinthe step of smoothing the surface comprises abrading the surface withabrasive particles less than 50 micrometers in size.
 4. The method ofclaim 1 wherein the step of smoothing the surface comprises abrading thesurface with abrasive particles bonded to a carrier and the particlesare less than 50 micrometers in size.
 5. The method of claim 1 whereinthe step of smoothing the surface comprises abrading the surface withabrasive particles bonded to a carrier, the particles are less than 50micrometers in size, and the particles having an average nearestneighbor spacing less than about 4 times the size of the particles. 6.The method of claim 1 wherein the step of smoothing the surfacecomprises abrading the surface with abrasive particles, the particlesare bonded to a carrier and the particles are less than 50 micrometersin size, the step of smoothing continuing until the surface attains theminimum surface roughness for the particle size.
 7. A method ofconditioning a resin impregnated fiber pad comprising the step ofconditioning the surface of the pad with abrasive particles bonded to asubstantially solid surface wherein the particles have an averagenearest neighbor spacing less than about 4 times the average size of theparticles and the particles having a size of less than 50 micrometers.8. The method of 7 wherein the particles have an average size less thanabout 30 micrometers.
 9. The method of 7 wherein the particles have anaverage size less than about 15 micrometers.
 10. The method of 7 whereinthe particles have a size in the range of about 1 micrometer to lessthan 50 micrometers.
 11. A pad conditioner for conditioning thepolishing surface of CMP pads, the conditioner comprising a conditionerbody, a carrier, and abrasive particles bonded to a carrier, the carrierbeing coupled to the conditioner body so as to provide a conditioningsurface comprising the particles, and the particles having a gritgreater than or equal to about
 400. 12. The conditioner of claim 11wherein the particles comprise at least one of diamond, silicon carbide,aluminum oxide, boron nitride and zirconia.
 13. The conditioner of claim11 wherein the particles comprise diamond.
 14. A pad conditioner for atleast one of CMP pads and polishing pads, the conditioner comprisingabrasive particles bonded to a carrier, the particles having a size lessthan 50 micrometers and the particles having an average nearest neighborspacing less than about 4 times the size of the particles.
 15. The padconditioner of claim 14 wherein the particles have an average nearestneighbor spacing less than about 3 times the size of the particles. 16.The pad conditioner of claim 14 wherein the particles have an averagenearest neighbor spacing less than about 2 times the size of theparticles.
 17. An apparatus for conditioning a pad for at least one ofchemical mechanical planarization and polishing a substrate, theapparatus comprising: a pad conditioner comprising an abrasive surfacecapable of producing the minimum surface roughness for the pad surfacefor a size of abrasive particles, the abrasive particles being less than50 micrometers in size, and a pad support for supporting the pad, thepad conditioner and pad support being coupled so as to allow the padconditioner to condition the pad.
 18. The apparatus of claim 17 whereinthe pad support comprises a turntable.
 19. The apparatus of claim 17wherein the pad conditioner comprises abrasive particles between 1micrometer and 50 micrometers in size.
 20. The apparatus of claim 17wherein the pad conditioner comprises abrasive particles less than about30 micrometers in size.
 21. The apparatus of claim 17 wherein the padconditioner comprises abrasive particles less than about 15 micrometersin size.
 22. The apparatus of claim 17 wherein the pad conditionercomprises abrasive particles bonded to a carrier.
 23. The apparatus ofclaim 22 wherein the pad conditioner comprises abrasive particlesselected from the group consisting of silicon carbide particles,aluminum oxide particles, and zirconia particles.
 24. The apparatus ofclaim 22 wherein the pad conditioner comprises diamond particles bondedto a carrier.
 25. A method of conditioning a pad for at least one ofchemical mechanical planarization and polishing a substrate, the methodcomprising the step of generating a surface on the pad having a surfaceroughness less than the minimum surface roughness achievable usingabrasive particles less than 50 micrometers in size.
 26. A method ofconditioning a resin impregnated fiber pad for at least one of chemicalmechanical planarization and polishing a substrate comprising the stepof abrading the surface of the pad with particles having an average sizeless than 2 times the average diameter of the fibers.
 27. A method ofclaim 26 wherein the particles have an average size less than 1 timesthe average diameter of the fibers.